This invention relates to a damper for solar heating systems and the like.
In a solar heating system, a plurality of dampers are usually utilized to control the flow of heated air between a solar collector, a storage area and a utilization area such as a house. In view of present-day concern over conservation of energy, it is important that such systems are as tight and free of leakage as possible. It is especially desirable to prevent leakage back from the plenum toward the collector itself.
Prior motorized damper assemblies have usually utilized a seal member which sealed the edge of the damper to its peripheral frame. However, this has required that the motor bring the damper blade up to a fixed stop position before the seal was made. Warpage of the damper blade and improper adjustment of the motor control have caused undesirable leakage to occur at the seal area.
Warpage of the damper blade can be caused by many factors. Many damper systems utilize a single motor for operating a pair of damper blades, with a connector rod connecting the blades. This puts a strain on the blades, causing them to warp. An additional cause of warpage has been the damper blade mounting to an axial member which has been mounted to the blade in such a way that the blade tended to bend about the member. Other factors include torque forces and temperature changes.
The present invention is directed to an improved damper assembly which eliminates or reduces the effect of some of the aforementioned problems and which provides an improved sealing of the closed damper with accompanying reduced air leakage therethrough.
In accordance with one aspect of the invention, the damper blade is surrounded by a peripheral flexible sealing element which extends inwardly from the surrounding frame and which is inclined in a direction against the direction of closing damper blade movement. As the damper moves toward a closed position, its sides progressively engage the side portions of the sealing element, with the latter providing a seal with the peripheral face of the blade, as opposed to the edges thereof. The ends of the blade engage the sealing element prior to the blade finally reaching its ultimate closed position, with the sealing being complete at the moment of engagement and throughout the final range of blade movement. Thus, if the motor controls are improperly set or the damper blade is warped so that the blade does not reach its fully closed position, complete sealing will nevertheless take place.
In accordance with an additional aspect of the invention, the peripheral sealing element is mounted to a subframe which is adjustable on the main frame to thereby sealingly accommodate a warped damper blade.
In accordance with a further aspect of the invention, the damper blade is mounted for axial rotation on pins in such a manner that the previous tendency of the mount to bend the blade is substantially eliminated.
In accordance with yet another aspect of the invention, the blade mounting pins are journalled for rotation in bearings having square exteriors and which are disposed very closely adjacent the squared-off ends of the subframe portions to reduce the possibility of leakage in the bearing area.
Finally, the damper blade-bearing assembly is spring loaded axially to reduce tolerance problems.